Lockbolt type fasteners typically have a shaft with a series of annular protrusions or spirals and grooves. One set of grooves receives material from a collar that is placed around the bolt, the collar swaged such that it deforms to fill the grooves. Another set of grooves, located on the pintail, is gripped by a puller of a fastener installation tool during the swaging process. The portion of the lockbolt with the protrusions to be gripped by the fastener installation tool is commonly referred to as a pintail. The fastener installation tool typically has an anvil with a smaller interior diameter than the outer diameter of the collar to be swaged to the lockbolt. The puller pulls the lockbolt and collar into the anvil, thus swaging the collar to the lockbolt and breaking off the pintail.
To facilitate the breaking off, lockbolts include a neck area between the sets of grooves, the neck area distinguishing the main lockbolt from the pintail. The neck area provides a weak point in the lockbolt to enable the pintail to be removed, or broken off, after the collar has been swaged. Removal of the pintail is typically accomplished with the puller continuing to apply force to the lockbolt after the swage operation has been completed.
One example of a lockbolt installation tool can be found in U.S. Pat. No. 7,921,530, incorporated herein by reference.
Some current tool designs produce interference, or rubbing, of the puller against the lockbolt while the tool is being positioned. The rubbing causes wear and tear on the tool and requires care to ensure that the lockbolt is not pushed out of place in the workpiece by the puller. The puller can also protrude from the end of the tool, giving unnecessary exposure to the puller.